Alloy



Patented July 21, 1936 I e v v UNITED STATES PATENT OFFICE 2,048,239 Roy T. witth E lfzlevelalld, Ohio No Drawing. Application November 14, 1929,-

Serial No. 407,296

1 Claim. (01. 75-136) The present invention relates to extremely hard from as low as 10 percent to as high as 75 percent, alloys which are particularly adapted for use in while the. tungsten or molybdenum or the combithe manufacture of high speed cutting tools or nation thereof may likewise be varied from 20 implements subject to abrasion although they percent to nearly 90 percent. The-carbon con- 5 may be used for various other purposes. The tent increases with the chromium content inas- 5- alloys are made up of chromium, carbon, and much as the maximum amount of carbon which one or more .of the other metals of the chromium can be dissolved in and/or combined with tunggroup, preferably either tungsten or molybdenum sten without" forming graphite is less than the alone or a combination of the two. The compoamount of carbon which can be dissolved in sition of such alloys may be varied within wide and/or combined with chromium without form it) limits, but within these limits furnishes alloys of ing graphite. I extreme hardness and alloys which are useful in In making such alloys, particularly where high the manufacture of cutting tools or similar imcarbon contents are. employed, itis preferable to plements. In addition the present invention inuse the elements in thepowdered form, and to 5 chides a method of using such high carbide alloys mix them together in the desired proportions and i5 and in forming cutting tool alloys having definite then to press slugs of the mixed powders, a suitlimits of composition by the addition of the above able binding material being added to hold the type of carbide alloy to a second alloy of adifpowders in shape, if desired. The pressed slugs ferent composition. are then hea" ad or fused to form the final alloy.

In my ,co-pending applications, Serial No. These alloys can also be made by using the metal-. 20 81,085, filed Jan. 13, 1926; and Serial No. 448,433 lic carbides, such as exist in the final alloys, in filed Apr. 29, 1930; I have described alloys using the powdered form. Where this is done, the carehromium in combination with carbon, and one bides are formed .separately, powdered to a suitor more of the metals of the iron group, preferable fineness, mechanically mixed with chromium,

a continuation in part of my applications, Serial then sintered or melted to form the final alloy.

No. 81,085, filed Jan. 13, 1926; Serial No. 448,433, In alloys of the present type, it is to be underfiled Apr. 29, 1930; Serial No. 405,540, filed Nov. I, stood, of course, that the usual impurities are 1929; and Serial No. 408,414, filed Nov. 19, 1929; I present; that is, that there may be small quantihave found that by changing the composition, ties of other metals such as iron, or the like, and 30 that is, by alloying chromium, carbon and one or also that special elements such as titanium, zir- 4 more of the other metals of the chromium group, conium, tantalum, and the like, may be added in such as tungsten or molybdenum, it is possible to small quantities to give special properties .to the produce even. harder alloys which, while useful alloys, and that where such special elements are in themselves for some purposes, are even more added they are in such small quantities that the 35 usefulto add to other alloys to obtain a desired, main alloy is always substantially a composition definite, final alloy. of chromium, carbon, and one or more of the Th all y contain h m m. ar n and tun other metals of the chromium group. Cobalt, or sten, chromium, carbon and molybdenum, or one or more of the metals of the iron group may chromium, carbon, tungsten and molybdenum, be present up to 10 percent, but where present, 40 n h f l win lyses give typi xamples "must beheld low enough not toafiect the carbide of h y formation of the alloy. I

In using these alloys which are essentially a Tungsten and/mcarblde alloy, that is, the alloy is essentially comchromium Carbon g gg g g gga posed of carbides of the metals present, they can im i i be mixed with other alloys to produce final alloys of definite compositions. In making such final or" mixed alloys it has been found that where a carbide or a carbide alloy of the type previously eases results are obtained where the second alloy contains the metal or metals of the first carbide alloy It will be seen from the analyses that the caras well as metals of a difi'erent group. ,It has bon varies from about three percent to 12 likewise been found that if a-straight metallic percent. The'chromiu'm can likewise be varied carbide is used, such as either chromium or tung- 5 ably cobalt. In the present invention; which is tungsten, carbon, or powdered alloys thereof, and 5" described is added to a second alloy, that excellent 50 sten carbide, it may be advantageously added to 8. molten alloy containing the metal of the carbide and another metal. Such carbide alloys are hereinafter designated as A metals. These A metals may be added or mixed with 8 metals which should contain the metal or metals of the essential carbide or carbides of the "A" metal together with a metal or metals of another group, preferably metals of the iron group such as oobalt, the 3" metal containing carbon as well, but preferably an insufiicient amount of carbon to have a particularly high carbide content. The following examples are given:

IAN IIB" Carbon. 8.5-9 Chromium 24-28 Chromium Tungsten 12-18 Tungsten Cobalt 64-54 and 32-36 Carbide Low as-pouible Impurities Resultant Carbon 3m ghromti aum --.L --38-58 n not less than 15 percent) m finot less than 6 percent) Chromium 1254-15 Chromium 7-8 Tungsten.. 76-80 Tungsten 38-42 c and 6%? Cobalt;l or n an Impurities Balm Low carbon Resultant Carbon 1-7 Chromiurm -l 15 Cobalt t less than percent Tungsten Not less than38pereent Thus the present alloy as well as the method of using the same gives unusual results, and particularly the method is the adding of an A metal, that is, a metal composed essentially of metallic carbides to a B metal which is an alloy composed of the metakor metals in the A" metal together with a metal of another group which is preferably a metal of the iron group. The 13" metal is preferably melted as this can be readily done where the 3 metal does not contain a high carbide content, and the A metal is then added, and the two mixed to form the resultant alloy. In such mixing operation it is often desirable to powder the "A" metal, press into slugs, and to add such slugs to a molten or fused bath of the "13 metal and then thoroughly mix before pouring, casting, or cooling the resultant alloy.

In addition an 9A" metal may also be added to a 3" metal where the two metals both contain the same carbide such as the following:

It is also possible to employ the method shown in my copending application, Serial No. 405.540, filed Nov. 7, 1929, which would consist of powdering both the A" and the B metal, mixing in the desired proportions. pressing the resultant mixed powder to the desired shape, and then sintering such pressed shapes to form the final alloy. It is also possible to make the resultant alloy, which is desired, by the first method of casting, and then to break such alloy down into powder, press to shape and sinter to form the finished tool or implement, this, of course, not changing the composition of the final alloy.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the process herein disclosed or the materials employed in carrying out the process, provided the step or steps stated by any of the following claimsor the equivalent of such stated step 'or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

A sintered alloy comprising carbon 8.5% to 9.0%, chromium to and tungsten 32% 

